Fluid actuated collet chuck



Jan. 22, 1946. G. w. COOK 2,393,458

FLUID ACTUATED COLLT CHUCK Filed Aug. 22, 1944 2 sheets-sheet 1 v Il? V-E 17 -l- Jan. 22, 1946.

/5 /ev /s 57 zo G. IW. COOK FLUID ACTUATED COLLET CHUCK Filed `Aug. 22, 1944 '4 Z'Sheets-She'et 2 E'EDl-gl? TU. Baal:

Patented Jan. 22, 1946 FLUiD AcrtJATED cortar CHUCK cergefyvgcook, Los-"Angele'sf, cal1if. l Appiicatioii gust 22, 1944,.'serim51510,;550,565 ajolaims. (01."279-44) inventionv relates tothe art of chucks and similar devices adapted tohold and toioperate collets. Such devicesare `particularlyuseful in the courseof varioustypes of machining :operations where a succession of duplicate articles is sequently'toA release it for removal.

The device of my invention is capable of awide variety of uses, aswill be understood -bythose skilled in the art. Forthe purpose of the following description of a' preferred and illustrative form ofl the invention, it will be assumed that thechuck-is used on a drill press, for suchoperations as those which a vdrill press iscapable .of performing. -Such use howeveris not a: limitation upon the invention. n

Eurther vrand more lparticular objectsv of4 the invention, and itsfcorresponding :features Vand accomplishments, will be best understoodffrom the following detailed description of the present preferred and illustrative form of therinvention, reference being had to theaccompanyingdrawings, in which Fig. lis a bottomplan'of theillustrative chuck,

and Fig. 2 is a section taken on. line 2-.-.2,of'1ig. v1.

`As shown in the drawings the chuck has a main housing member Ill provided witha seatingfflange Ilv at its lower edge adapted. torest'upon,v or be clamped or bolted 'to the table of adrill' press, Lor tothe face plate,;tableor base of any othermachine tool where the4 chuck may be used. As fused on a drill press, the chuck may ordinarily' Ybe clamped inposition on theftable, f Y ,Housing. II)` contains an annular cylinder .I2 which is formedbetweenl outer circularwall I3 of the housing and an inner dependingcylindric sleeve I4. -A head wall YI3a closes the upper end of the annular cylinderthe lower end of which is open. This head wall is `made Vfairly thick,l as illustrated, allowing holes to be drilled and tapped into it for mounting drill orrwork jigs on top of the chuck body. Theinteriorpbore'IE of sleeve 4iis adapted to snugly takecolletadapters of a common ,external size and of. various internal sizes to suit the external dimensions Aof different sets of collets. A typical adapteris shown at IG, secured in place by cap screws I1. -;'I'he interior bore I B of the adapter has the usual and standard conical collet seat I9 at its upper end.- The collet, illustrated at 20 is a standard collet.

The adapter I 5 may be considered as a part of the sleeve I4, its only functions being to provide a collet seating I9 of a metal more suitable for,V that purpose than rthe metal of the main housing will ordinarily` be, and to facilitate adaptation to collets of 1 different external sizes.

Asidefrom those provisions the whole device functionsias ifadapter IB were unitary with sleeve I4,and.thus the'sleeve I4 can `be said to have or 'contain vthe, collet receiving bore I8',fI9.

.Preferably somek .keying means is `employed either to prevent or, preferably, to-yieldingly resist, relative rotation of Athel collet `in the adapter. The standardcollet hasga longitudinal keyway 2 I,.usually.=engaged by a solid pin or key in 4the adapter;v Such a solid pin or key' may be vused in-my chuck, but I prefer for reasons which will' appear to utilize^-a1spring pressedr ball ,22, pressed. inwardly byv a spring 23l into yielding engagement .with keyway 2|.r sorthat. the .collet .will ordinarily. be` heldY from rotation` vin the adapter, but may be rotatedtherein by the application of suf'cient force.

t f AnA annular piston 30, with, an annular' cup .leather or rubber 3 I-,l operatesin annular cylinder -I2,.supported ona series of springs 32.which raise the piston in the cylinder;A The piston is lowered by air or1other'fluidpre'ssure introduced tothe cylinder by way of port 33 and piping 34'which will .be controlled, by any suitable type of valve lcapable of alternately admitting and exhausting pressure.y Foot valvesor foot controlled valves .0f knownI-typesareconvenient `Springs 32re's't aty thirlllower ends`on mounting lugs 35vwhich are secured to the inside face of housing wall I3 by the cap screws Y36 shown in Fig. l. i

ffArota'table ringfAis mounted Yonthe under sider of annular-piston lStrand carried thereby. The lower face of .piston 30 has, at its inner ledge, an annular machined surface *4I` against which a vmacl'iined shoulder surface 42k of ring 40 bears upwardly. 'i An Vinternal ,annular shoulder 43 yis formed on vthe piston, anda ring 44 which is secured' to'ring 40 v'by cap screws 45, bears doWnf wardly'on shoulder 43.', When` cap screws 45 are f setup solidly,v the spacing between ring shoulder 42 and the lower 'face of ring 44 is such, with relation tothe'spacing'between piston face 4! and shoulder 43 thatl ring 40 is .locked tov the piston and is thus held against rotation. By loosening screws 45, the ring is then' readily .rotatable on av vertical central axiswith relation to the piston, withoutany excessive vertical looseness.

' Rotatablering 40 carries a central changeable bushing 50, preferably set intov'ring 4E! by threading, andhaving an. internal threading 5I adapted totake the'collet threads 52 of standard collets. Bushing r5l! isset tightly in ring 4B to rotate with the ring, and the ring and bushing together form what may be termed a collet nut which takes the lower threaded end ofthe standard collet and is rotatable with reference to the piston and to the other parts .of the device, and with reference to the collet.

A readily removable stop bracket is provided for the purpose of carrying an adjustable stop to limit the insertion of the work into the collet. As here shown, this `stop bracket -comprisesailat bar 54 extending across the bottom interior of the main housing and secured to two of theA mounting lugs 35 by screws 55. An adjustable stop, preferably in the form of a long vertical threaded screw or bolt 56 is screw-threadedly mounted in bracket 54, with its head uppermost.

I2 allows the piston to be moved up by springs 32, moving the collet up with it high enough to allow the collet head to expand. A limit stop for the upward motion is preferably formed by ring Merengaging the lower end of sleeve N, rather .than by ring Ill-or bushing Sqfengag-ing the lower end of adapter I6. Dirt and chips may lodge between 50 and I6, but the space between 44 and i4 is closedv by .the lower end of the adapter i6 projecting below the upper face of 44 and into its bore 4and that yof ring 40 with' a, fairly close fit.

A screwhead of any suitable form may be `used;-

a slotted head is here shown which may easily be reached with an ordinary screw driver through the jaw bore 51 of Vthe collet. The stop may thus easily be set up and down within the collet to `standardize the insertion of the work into th'e collet. The projecting lower end .of the long adjustable stop screw may `project throughan opening Iin the table or face plate; or, for any particular set-up, the stop screw 56 -maybe Vcut to special length for the particular job, so `that there lis noprojecting end.

In setting up the chuck for any particular job, .the `collet adapter I6 will be selected to suit the external dimensions of the particular collet or collets employed. Due to the fact lthat some .of these adapters may be rather thin Walled, the Adetent .spring12'3 may preferably have its 'rear end bearing against the bore l5, as illustratedfinstead of bearing againsta seat within the wall of vthe adapter. vAfter inserting the selectedadapter, the selected collet is th'en inserted intothe adapt'- er. The collet may then be screw-threadedly pulled down inthe ycollet nut, either by loosening screws-45 and rotating the nut before the chuck is secured to Ithe table or face plate, or by rotating the collet with `suiiicierlt force to make the spring-pressed ball l22 yield. The first mentioned procedure is the preferred and normal one, the collet being held against rotation by the springpressed ball while the collet :cutis being rotated to draw the collet into the Ynut to itsvproper operating position-a relative position such as shown in Fig. 2. After the collet has been set in its operative position by nut rotation, screws 45 are then set up to hold the nut from rotation. However, if the chuck is already set and alined on the table or face plate, and it is desired to change collets without disturbing the setting of the chuck, a new collet may be inserted and threaded into position by rotating the collet. Although the collet nut may be relatively freely rotatable on the piston if screws 45 are not set up, the small amount of friction at the ,threads 5|, 52and the mass of the collet nut, enable the collet to be rotated and threaded into the relatively stationary nut. Normally, however, the nut will be locked against rotation, by screws 45, when a collet is threaded into position by rotating the collet.

Fig. 2 shows the chuck in its actuated or workgrippingrposition, with the h'ead of the collet drawn down in conical boreI I9 and compressed in a position to hold the work. Fluid pressure is at .this time present in cylinder I2, pressing and holding the piston and the collet down. With the work thus gripped, any desired operation, or series of operations, may be carried out on the Work. Immediately the operation or operations are completed, release of pressure from cylinder Iclaim:

1.'In'a iluid pressure actuated collet chuck, a bodyhaving an external cylindric wall, an upper head wall and an internal sleeve depending from the :head WalLwhich walls form a downwardly .opening annular cylinder, `an annular piston in the-cylinder adapted to be rforced downwardly y'by fluid pressure inthe cylinder, the sleeve 4containing a vertical collet receiving-bore with-a, coni-cal :counterbore at its :upper end yadapted to `engage with the conical 'head of -a -collet to contract the collet head on its downward movement in the bore, and an annular collet nut Vbelow thelower `end of the sleeve bore, said nut mounted on the piston to move vertically-therewith but to be rotatable with reference thereto, and having la central screw threaded bore to take the lower screw threaded end of a collet which is in the sleeve bore. l

2'. In 'a iiuidpressure actuated collet chuck, a body having an external cylindric wall, an upper head wall and an internal vsleeve depending from the head wall, which walls form a downwardly -opening annular cylinder, an annular piston in `the cylinder adapted to be forced downwardly by `iiuid pressure in the cylinder, the sleeve containing a Vertical collet receiving bore with a corneal counterbore at its upper end adapted to engage with the conical head of a collet to contract the collet head on its downward movement in the bore, an annular collet nut below the lower end of the sleeve, said nut being of an external' diam- -eter greater than the internal diameter of the pisy ton and having an upper annular-face which bears upwardly against a lower face of the piston, the piston having an upwardly facing annular shoulder, a bearing ring secured to the nut and bearing down on the piston shoulder, the -nut being rotatable onthe vertical axis of the sleeve bore with reference to the piston, and the nut having a central threaded bore adapted to take the lower 'threaded end of a collet which is in the sleeve bore. I

3. In a fluid pressure actuated collet chuck, a body having an external cylindric wall, an upper head wall and an internal sleeve depending from the head wall, which walls form a downwardly opening annular cylinder, an annular piston in the cylinder adapted to be forced downwardly by fiuid pressure in the cylinder, the sleeve containing a vertical collet receiving bore with a conical counterbore at its upper end adapted to engage with the conical head of a collet to contract the collet head on its downward movement in the bore, an annular element mounted on th'e piston to move vertically therewith below the lower end of the depending sleeve, said element provided with means to take and hold the lower end of a collet which is in the sleeve bore.

' GEORGE W. COOK. 

